perf tests test_brstack.sh: Fix all POSIX sh warnings

Fix all the POSIX sh warnings in perf shell test test_brstack.sh
Warnings fixed :
* In POSIX sh, using lower/mixed case for signal names is undefined.
Correcting that in this script.
* In POSIX sh, 'local' is undefined.
local is supported in many shells, but it's not in POSIX.
In POSIX sh, you can adopt some convention to avoid accidentally
overwriting variables names, e.g. prefixing with the function name,
that is what I have done here.
Signed-off-by: Geetika <geetika@linux.ibm.com>
Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230613164145.50488-14-atrajeev@linux.vnet.ibm.comSigned-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/shell/test_brstack.sh

@@ -18,7 +18,7 @@ cleanup() {
 	rm -rf $TMPDIR
 }
 
-trap cleanup exit term int
+trap cleanup EXIT TERM INT
 
 test_user_branches() {
 	echo "Testing user branch stack sampling"
@@ -47,17 +47,17 @@ test_user_branches() {
 # first argument <arg0> is the argument passed to "--branch-stack <arg0>,save_type,u"
 # second argument are the expected branch types for the given filter
 test_filter() {
-	local filter=$1
-	local expect=$2
+	test_filter_filter=$1
+	test_filter_expect=$2
 
-	echo "Testing branch stack filtering permutation ($filter,$expect)"
+	echo "Testing branch stack filtering permutation ($test_filter_filter,$test_filter_expect)"
 
-	perf record -o $TMPDIR/perf.data --branch-filter $filter,save_type,u -- ${TESTPROG} > /dev/null 2>&1
+	perf record -o $TMPDIR/perf.data --branch-filter $test_filter_filter,save_type,u -- ${TESTPROG} > /dev/null 2>&1
 	perf script -i $TMPDIR/perf.data --fields brstack | xargs -n1 > $TMPDIR/perf.script
 
 	# fail if we find any branch type that doesn't match any of the expected ones
 	# also consider UNKNOWN branch types (-)
-	if grep -E -vm1 "^[^ ]*/($expect|-|( *))/.*$" $TMPDIR/perf.script; then
+	if grep -E -vm1 "^[^ ]*/($test_filter_expect|-|( *))/.*$" $TMPDIR/perf.script; then
 		return 1
 	fi
 }